Methods of ablating tissue using a catheter injection system

ABSTRACT

At the present time, physicians often treat patients with atrial fibrillation (AF) using radiofrequency (RF) catheter systems to ablate conducting tissue in the wall of the Left Atrium of the heart around the ostium of the pulmonary veins. These systems are expensive and take time consuming to use. The present invention circular ablation system CAS includes a multiplicity of expandable needles that can be expanded around a central axis and positioned to inject a fluid like ethanol to ablate conductive tissue in a ring around the ostium of a pulmonary vein quickly and without the need for expensive capital equipment. The expansion of the needles is accomplished by self-expanding or balloon expandable structures. The invention includes centering means so that the needles will be situated in a pattern surrounding the outside of the ostium of a vein. Also included are members that limit the distance of penetration of the needles into the wall of the left atrium. The present invention also has application to ablating tissue around the ostium of a renal artery for the treatment of hypertension.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/814,962, filed on Jul. 31, 2015, which is a continuation of U.S.patent application Ser. No. 14/057,972, filed on Oct. 18, 2013, nowissued as U.S. Pat. No. 9,131,983, which is a divisional of U.S. patentapplication Ser. No. 13/092,363, filed on Apr. 22, 2011, now issued asU.S. Pat. No. 8,663,190. The entirety of each of the foregoingapplications is hereby incorporated by reference herein.

FIELD OF USE

This invention is in the field of devices to ablate muscle cells andnerve fibers for the treatment of cardiac arrhythmias and/orhypertension.

BACKGROUND OF THE INVENTION

At the present time, physicians often treat patients with atrialfibrillation (AF) using radio frequency (RF) catheter systems to ablateconducting tissue in the wall of the Left Atrium of the heart around theostium of the pulmonary veins. Similar technology, using radiofrequencyenergy, has been used inside the renal arteries to ablate sympatheticand other nerve fibers that run in the wall of the aorta on the outsideof the renal arteries, in order to treat high blood pressure. In bothcases these are elaborate and expensive catheter systems that can causethermal, cryoablative, or other injury to surrounding tissue. Many ofthese systems also require significant capital outlays for the reusableequipment that lies outside of the body, including RF generation systemsand the fluid handling systems for cryoablative catheters.

Because of the similarities of anatomy, for the purposes of thisdisclosure, the term target vessel will refer here to either thepulmonary vein for AF ablation applications or the renal artery forhypertension therapy applications. The term ostial wall will refer tothe wall of the Left Atrium surrounding a pulmonary vein for AFapplication and to the wall of the aorta for the hypertensionapplication.

In the case of atrial fibrillation ablation, the ablation of tissuesurrounding multiple pulmonary veins can be technically challenging andvery time consuming. This is particularly so if one uses RF cathetersthat can only ablate one focus at a time. There is also a failure rateusing these types of catheters for atrial fibrillation ablation. Thefailures of the current approaches are related to the challenges increating reproducible circumferential ablation of tissue around theostium (peri-ostial) of a pulmonary vein.

There are also potential risks using the current technologies for RFablation to create sympathetic nerve denervation inside the renal arteryfor the treatment of hypertension. The long-term sequelae of applying RFenergy inside the renal artery itself are unknown, but this could leadto late restenosis, embolization of debris into the renal parenchyma, orother problems inside the renal artery. There may also be uneven orincomplete sympathetic nerve ablation, particularly if there areanatomic abnormalities, or atherosclerotic or fibrotic disease insidethe renal artery, such that there is nonhomogeneous delivery of RFenergy. This could lead to treatment failures, or the need foradditional and dangerous levels of RF energy to ablate the nerves thatrun along the adventitial plane of the renal artery. There are alsosignificant safety issues with current technologies related to very longfluoroscopy and procedure times that lead to high levels of radiationexposure to both the patient and the operator, and may increase strokerisk in atrial fibrillation ablation.

Finally, while injection of ethanol as an ablative substance is usedwithin the heart and other parts of the body, there has been nodevelopment of an ethanol injection system specifically designed forcircular ablation of the ostial wall of a target vessel.

SUMMARY OF THE INVENTION

The present invention Circular Ablation System (CAS) is capable ofproducing damage in the tissue that surrounds the ostium of a bloodvessel in a relatively short period of time using a disposable catheterrequiring no additional capital equipment. The primary focus of use ofCAS is in the treatment of cardiac arrhythmias and hypertension.

Specifically, there is a definite need for such a catheter system thatis capable of highly efficient, and reproducible circumferentialablation of the muscle fibers and conductive tissue in the wall of theLeft Atrium of the heart surrounding the ostium of the pulmonary veinswhich could interrupt atrial fibrillation (AF) and other cardiacarrhythmias.

This type of system may also have major advantages over other currenttechnologies by allowing time efficient and safe circumferentialablation of the nerves in the wall of the aorta surrounding the renalartery (peri-ostial renal tissue) in order to damage the sympatheticnerve fibers that track from the peri-ostial aortic wall into the renalarteries, and thus improve the control and treatment of hypertension.Other potential applications of this approach may evolve over time.

The present invention is a catheter which includes multiple expandableinjector tubes arranged circumferentially around the body of the CASnear its distal end. Each tube includes an injector needle at its distalend. There is a penetration limiting member proximal to the distal endof each needle so that the needles will only penetrate into the tissueof the ostial wall to a preset distance. This will reduce the likelihoodof perforation of the ostial wall and will optimize the depth ofinjection for each application. The injector needles are in fluidcommunication with an injection lumen in the catheter body which is influid communication with an injection port at the proximal end of theCAS. Such an injection port would typically include a standard connectorsuch as a Luer connector used to connect to a source of ablative fluid.

The expandable injector tubes may be self-expanding made of a springymaterial or a memory metal such as NITINOL or they may be expandable bymechanical means. For example, the expandable legs with distal injectionneedles could be mounted to the outside of an expandable balloon whosediameter is controllable by the pressure used to inflate the balloon.

The entire CAS is designed to be advanced over a guide wire in either anover the wire configuration where the guide wire lumen runs the entirelength of the CAS or a rapid exchange configuration where the guide wireexits the catheter body at least 10 cm distal to the proximal end of theCAS and runs outside of the catheter shaft for its proximal section.

The distal end of the CAS also includes a centering means at or near itsdistal end. The centering means could be a mechanical structure or anexpandable balloon. The centering means will help to ensure that theinjector tubes will be engaged circumferentially around and outside ofthe ostium of the target vessel. If the injector tubes are expanded by aballoon, then it is envisioned that the distal portion of the balloonwould have conical or cylindrical distal portions that would facilitatecentering the CAS in the target vessel.

The CAS would also be typically packaged inside an insertion tube thatconstrains the self-expanding legs prior to insertion into a guidingcatheter, and allows the distal end of the CAS to be inserted into theproximal end of a guiding catheter or introducer sheath.

The CAS might also be packaged to include an outer sheath that runs theentire length of the CAS so as to cover and protect the needles and alsoprotect them from getting caught as the CAS is advanced distally to thedesired location.

It is also envisioned that the injection needles could be formed from aradiopaque material such as tantalum or tungsten or coated with aradiopaque material such as gold or platinum so as to make them clearlyvisible using fluoroscopy.

It is also envisioned that one or more of the injector needles could beelectrically connected to the proximal end of the CAS so as to also actas a diagnostic electrode(s) for evaluation of the electrical activityin the area of the ostial wall.

It is also envisioned that one could attach 2 or more of the expandablelegs to an electrical or RF source to deliver electric current or RFenergy around the circumference of a target vessel to the ostial wall toperform tissue ablation.

For use in the treatment of AF the present invention CAS would be usedwith the following steps:

-   -   Access to the left atrium via a large peripheral vein, such as        the femoral vein, typically with the insertion of a sheath.    -   Use a trans septal approach to get into the left atrium, via the        vein, to the right atrium, to enter the left atrium. This        approach is a well known procedure.    -   Advance a guide wire and guiding catheter across the        inter-atrial septum into the left atrium.    -   Using a guiding catheter with a shaped distal end or guiding        sheath, engage the first targeted pulmonary vein. This can be        confirmed with contrast injections as needed.    -   Advance a guide wire through the guiding catheter into the        pulmonary vein.    -   Place the distal end of an insertion tube which constrains the        distal end of the CAS into the proximal end of the guiding        catheter.    -   Advance the distal end of the CAS into and advance the CAS        through the guiding catheter, and tracking over the guidewire,        until it is just proximal to the distal end of the guiding        catheter.    -   Advance the CAS over the guidewire until the distal portion of        its centering means is within the target vessel.    -   Expand the centering means. If the centering means is        cylindrical, expand it until it is just slightly less (1-4 mm        less) than the diameter of the target vessel. This will ensure        that the catheter will be roughly “centered” within the target        vessel to enable the circumferential deployment of the legs of        the CAS around the target vessel ostium so that injection will        be centered around the ostium of the target vessel.    -   Pull back the guiding catheter to leave space for the expanding        injector tubes to open.    -   Expand the injector tubes or let them expand if they are        self-expanding. If balloon expandable, adjust the balloon        pressure to get the desired diameter. If selfexpanding, the        circumference of the self-expansion can be adjusted in vivo by        varying the distance of the pullback of the guiding catheter.        That is, if one wants a smaller diameter (circumference)        expansion to fit the ostial dimension of that specific target        vessel, one can partially constrain the injector tube expansion        by not fully retracting the guiding catheter all the way to the        base of the tubes. However, the preferred method is to have the        final opening distance be preset for the CAS, with the injector        tubes fully expanded to their memory shape. Typically the CAS        size would be pre-selected based on the anticipated or measured        diameter of the ablation ring to be created, such that the fully        expanded injector tubes create the correctly sized ablation        “ring.”    -   Advance the CAS until the injector needles at the distal end of        the self-expanding injector tubes penetrate the ostial wall,        with the penetration depth being a fixed distance limited by the        penetration limiting member attached to each needle at a preset        distance proximal to the distal end of the needle. If the        centering means is conical, as the CAS is advanced distally, the        cone will engage the ostium of the vein which will center the        CAS.    -   Attach a syringe or injection system to the injection connector        at the CAS proximal end.    -   Engagement of the ostial wall can be confirmed by injection of a        small volume of iodinated contrast via a syringe, through the        needles, prior to injection of the “ablative” fluid such as        alcohol. If there is contrast “staining” of the tissue this will        confirm that the needles are engaged into the tissue and not        free floating in the left atrium or aorta.    -   Inject an appropriate volume of ethanol (ethyl alcohol) or other        appropriate cytotoxic fluid from the syringe or injection system        through the catheter and out of the needles into the ostial        wall. A typical injection would be 1-10 ml. This should produce        a multiplicity of circles of ablation (one for each needle) that        will intersect to form an ablative ring around the ostium of the        target vessel. Contrast could be added to the injection to allow        x-ray visualization of the ablation area.    -   Once the injection is complete, retract the CAS back into the        guiding catheter, which will collapse the self-expanding        injector tubes. If the device is balloon expandable deflate the        balloon and retract back into the guiding catheter.    -   In some cases, one may rotate the CAS 20-90 degrees and then        repeat the injection if needed to make an even more definitive        ring of ablation.    -   The same methods as per prior steps can be repeated to ablate        tissue around the one or more of the other pulmonary veins        during the same procedure, as indicated to ensure AF inhibition.    -   Remove the CAS from the guiding catheter completely.    -   When indicated, advance appropriate diagnostic electrophysiology        catheters to confirm that the ablation has been successful.    -   Remove all remaining apparatus from the body.    -   A similar approach can be used with the CAS, via access from a        peripheral artery such as the femoral artery, to treat        hypertension, via ablation of tissue in the periostial aortic        wall tissue surrounding one or both of the renal arteries, with        the goal of ablating afferent and/or efferent sympathetic nerve        fibers entering or exiting the kidney.

It is also envisioned that two or more of the legs/injector tubes may beconnected to an electrical or RF field source to allow for electricaldischarge or RF ablation to enable tissue ablation of the tissue in theostial wall.

It is also envisioned that one could mount injector tubes with needleson the outer surface of an expandable balloon on the CAS in order todeliver 2 or more needles around the circumference of the ostium of atarget vessel to inject ablative fluid to the ostial wall.

In this case, the distal portion of the balloon could include thecentering means of a cylindrical or conical shape. This embodiment couldalso include an elastic band covering the injector tubes where theelastic band could both help maintain a smooth outer surface of the CASto facilitate delivery as well as act as the penetration limiting memberto limit the penetration of the injection needles.

Thus it is an object of the present invention CAS is to have apercutaneously delivered catheter that can be used to treat atrialfibrillation with a one, or more injections of an ablative fluid intothe wall of the left atrium surrounding one or more pulmonary veins.

Another object of the present invention CAS is to have a percutaneouslydelivered catheter that can be used to treat hypertension with one, ormore injections of an ablative fluid into the wall of the aortasurrounding a renal artery.

Still another object of the present invention CAS is to have apercutaneously delivered catheter that includes a multiplicity ofcircumferentially expandable injector tubes, each tube having a needleat its distal end for injection of an ablative fluid into the ostialwall of a target vessel.

Still another object of the present invention CAS is to have a centeringmeans located at or near the catheter's distal end. The centering meansdesigned to allow the injector to be centered on the target vessel sothat the injected ablative fluid will form an ablative ring outside ofthe ostium of the target vessel. The centering means can be fixed orexpandable, and may include a cylindrical or conical portion.

Another object of the invention is to have a penetration limiting memberor means attached to the distal portion of the injector leg or as partof the distal portion of the CAS in order to limit the depth of needlepenetration into the ostial wall.

Yet another object of the present invention CAS is to have one or moreof the injector needles act as diagnostic electrodes for measurement ofelectrical activity within the ostial wall of the target vessel.

These and other objects and advantages of this invention will becomeobvious to a person of ordinary skill in this art upon reading of thedetailed description of this invention including the associateddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a three dimensional sketch of the distal end of the presentinvention Circular Ablation System (CAS).

FIG. 2 is a longitudinal cross sectional drawing of the distal end ofthe CAS.

FIG. 3 is a longitudinal cross sectional drawing showing area 3 of FIG.2 which is the distal end of the self-expanding injector leg, injectorneedle and penetration limiter.

FIG. 4 is a longitudinal cross sectional drawing showing area 4 of FIG.2 which is the proximal end of the self-expanding injector legs and howthey are in fluid communication with the injection lumen of the CAS.

FIG. 5 is a three dimensional sketch showing the CAS with centeringballoon expanded.

FIG. 6A is a three dimensional sketch showing the CAS with legscollapsed inside the distal end of a guiding catheter as the distal endof the CAS is inserted into the target vessel.

FIG. 6B is a three dimensional sketch showing the CAS after the CAScentering means has been expanded and the guiding catheter has beenpulled back (retracted) allowing the self-expanding legs to expand.

FIG. 6C is a three dimensional sketch showing the CAS now advanced inthe distal direction until the injector needles penetrate the ostialwall and the penetration limiters on each needle limit the penetrationas they touch the ostial wall. In this configuration an ablativesubstance such as alcohol is injected into the ostial wall through theneedles causing a complete circular ablation of tissue in the ostialwall in a ring surrounding the target vessel.

FIG. 6D shows target vessel and ostial wall after the CAS and guidingcatheter have been removed from the body and the ablated tissue in theostial wall remains.

FIG. 6E is a three dimensional sketch showing the overlapping area ofablation in the ostial wall that form a circle around the ostium of thetarget vessel.

FIG. 7 is a longitudinal cross sectional drawing of the proximal end ofthe present invention CAS.

FIG. 8 is a longitudinal cross sectional drawing of an alternativeversion of the injector needle and penetration limiting means.

FIG. 9 is a longitudinal cross section of the CAS with the injectorneedle of FIG. 8 with the injector tubes shown collapsed inside theintroducer tube used to insert the CAS into the proximal end of aguiding catheter or sheath; and

FIG. 10 is a three dimensional sketch of an other embodiment of the CASthat uses a balloon to expand the expandable injector tubes used todeliver the ablative substance to the ostial wall of the target vessel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a three dimensional sketch of the distal end of the presentinvention Circular Ablation System (CAS) 10 in its state before it isloaded into a guiding catheter or sheath for delivery over the guidewire 20 into a human being. The proximal portion of the CAS 10 includesthree tubes, an outer tube 12, a middle tube 14 and an inner tube 18.The guidewire 20 can be slidably advanced or removed through the guidewire lumen 13 inside of the inner tube 18. An expandable cylindricalballoon 16 is attached at its proximal end to the middle tube 14 and atits distal end to the inner tube 18. The balloon inflation lumen islocated between the inner tube 18 and the middle tube 14. The balloon 16can be inflated by injection of a fluid through the balloon inflationlumen and deflated by applying suction to the balloon inflation lumen.

A injector transition manifold 11 is sealed onto the outside of themiddle tube 14. The outer tube 12 is sealed at its distal end onto theoutside of the injector transition manifold 11. The expandable injectortubes 15 are attached at their proximal end to or through the injectortransition manifold 11 so that the proximal lumen of the injector tubes15 are in fluid communication with the fluid injection lumen 22 thatlies between the middle tube 14 and the outer tube 12. The injectortubes 15 could be made of a springy metal such as L605 or the preferredembodiment being made from a memory metal such as NITINOL. A plastic hub17 is attached to the distal end of each injector tube 15. An injectorneedle 19 extends distally from the distal end of each plastic hub 17.The lumen of each injector needle 19 is in fluid communication with thelumen of the expandable injector tube (leg) 15. Each hub 17 acts as apenetration limiting member to limit the penetration of the distallyattached needle 19 into the ostial wall of the target vessel. In thisembodiment it is envisioned that the penetration of the needles 19 wouldbe limited to pre-set distance, for example the distance might bebetween 0.5 mm and 1 cm.

FIG. 2 is a longitudinal cross sectional drawing of the distal end ofthe CAS 10 in its state before it is loaded into a guiding catheter orsheath for delivery over the guide wire 20 into a human being. Theproximal portion of the CAS 10 includes three tubes, an outer tube 12, amiddle tube 14 and an inner tube 18. The guidewire 20 can be advanced orremoved through the guide wire lumen 13 inside of the inner tube 18. Anexpandable cylindrical balloon 16 is attached at its proximal end to themiddle tube 14 and at its distal end to the inner tube 18. The balloon16 may be either an elastic balloon or a folded inelastic balloon suchas is used for angioplasty. The proximal end of the balloon 16 isattached to the middle tube 14 and the distal end of the balloon 16 isattached to the inner tube 18 such that the area under the balloon 16 isin fluid communication with the balloon inflation lumen 24 that liesbetween the middle tube 14 and the inner tube 18. The balloon 16 can beinflated by injection of a fluid or gas through the balloon inflationlumen 24 and deflated by applying suction to the balloon inflation lumen24. Normal saline solution including a fluoroscopic contrast agent wouldbe the typical fluid used to inflate the balloon 16.

The injector transition manifold 11 is sealed onto the outside of themiddle tube 14. The outer tube 12 is sealed at its distal end onto theoutside of the injector transition manifold 11. The expandable injectortubes 15 are attached at their proximal end through the injectortransition manifold 11 so that the proximal lumen of the injector tubes15 are in fluid communication with the fluid injection lumen 22 thatlies between the middle tube 14 and the outer tube 12. FIG. 4 shows anexpanded version of the area 4 of FIG. 2. The injector tubes 15 could bemade of a springy metal such as L605 or the preferred embodiment beingmade from a memory metal such as NITINOL. A plastic hub penetrationlimiter 17 with flattened distal end to act as a means of limiting thepenetration of the needle 19 is attached over the distal end of each ofthe 8 expandable injector tubes 15. An injector needle 19 extendsdistally from the distal end of each plastic hub 17. The lumen of eachinjector needle is in fluid communication with the lumen of theexpandable injector tube 15.

FIG. 3 is an enlarged longitudinal cross sectional drawing showing area3 of FIG. 2 which is the distal end of the self-expanding injector tube15 with injector tube lumen 21, injector needle 19 and penetrationlimiter 17. While FIG. 3 shows the limiters 17 as being symmetric aroundthe injector tube 15, it is also envisioned that an asymmetricpenetration limiter, for example a limiter with significant materialonly on the inside might be preferable as it would be less likely tocatch on a guiding catheter when the CAS 10 is advanced through orretracted back into the guiding catheter at the end of the procedure.

FIG. 4 is an enlarged longitudinal cross sectional drawing of the CAS 10showing area 4 of FIG. 2 which is the proximal end of the self-expandinginjector tubes 15 with lumens 21. FIG. 4 shows detail on how the lumens21 of the injector tubes 15 are in fluid communication with theinjection lumen 22 of the CAS 10. Specifically, the proximal section ofeach injector tube 15 is inserted through a hole in the injectortransition manifold 11 and fixedly attached and sealed to the manifold11 so that the proximal end of the each tube 15 has its proximal end andopening in fluid communication with the injector lumen 22 that liesbetween the outer tube 12 and the middle tube 14 of the CAS 10. Asanother way of achieving this structure it is also conceived that theinjector manifold 11 might be a single piece of plastic molded over theproximal ends of the injector tubes 15 in a molding operation prior toassembly.

FIG. 5 shows a three dimensional sketch showing the CAS 10′ withcentering balloon 16′ expanded. Also shown are the outer tube 12, middletubeH and inner tube 18 with guidewire 20. The injector tubes 15protrude in the distal direction from the distal end of the injectormanifold 11 and have hubs 17 (penetration limiting members) withinjector needles 19 at their distal end. The expanded balloon 16′ shouldbe inflated to be just slightly less than the diameter of the targetvessel. This will allow it to act as a centering means without causingundue injury to the target vessel wall. Ideally, the balloon 16′ wouldbe a low pressure elastic balloon where the diameter can be adjusted byusing the appropriate pressure to inflate the balloon 16′ through theballoon inflation lumen 24. It is also conceived that the CAS 10′ wouldhave a non-compliant or semicompliant molded folded balloon with alimited diameter range vs. pressure such as is used in an angioplastyballoons.

FIG. 6A is a three dimensional sketch showing the CAS 10 with injectortubes 15 collapsed inside the distal end of a guiding catheter 30 as thedistal end of the CAS 10′ is inserted into the target vessel over theguide wire 20. The distal end of the guiding catheter 30 would normallyfirst be placed inside of the ostium of the target vessel (engaged) andis shown here slightly back from the ostium as it would be during thefirst part of its distal retraction. From the position shown in FIG. 6A,the guiding catheter 30 is pulled back (retracted) in the proximaldirection allowing the self expanding injector tubes 15 to spring opento their open position. The extent of leg expansion could be adjusted(limited and smaller) in vivo by not fully retracting the guidingcatheter, thus modestly constraining the expanded dimension of theexpandable tubes 15.

FIG. 6B is a three dimensional sketch showing the CAS 10′ after theguiding catheter has been pulled back and the inflatable balloon 16′ hasbeen expanded with the guide wire 20 still lying within the targetvessel. From this state, the CAS 10′ with expanded balloon 16′ isadvanced in the distal direction until the needles 19 penetrate theostial wall surrounding the target vessel. Engagement of the ostial wallcould be confirmed by injection of a small volume of iodinated contrastthrough the needles, prior to injection of the “ablative” fluid such asalcohol.

FIG. 6C is a three dimensional sketch showing the CAS 10″ now advancedin the distal direction with the injector needles 19 fully penetratingthe ostial wall and the penetration limiting members (hubs) 17 on eachneedle limiting the penetration as they touch the ostial wall. In thisconfiguration an ablative substance such as ethanol is injected into theostial wall through the needles 19. The ablative fluid will dispersefrom the needles and as more ablative fluid is injected, the area offluid dispersion shown in FIG. 6C will increase so as to eventuallycause a complete circular ablation of tissue in the ostial wall in aring surrounding the target vessel. The balloon 16′ is then deflated andthe CAS 10 is pulled back in the proximal direction until the needles 19are no longer penetrating the ostial wall. The CAS 10 is then pulledback more in the proximal direction into the distal end of the guidingcatheter 30 which will collapse the selfexpanding injector tubes 15. Atthis point the guide wire 20 may be advanced into another target vesseland the ablation procedure repeated. After the last target vessel istreated, the CAS 10 can then be removed from the patient's body. At thispoint electrophysiology catheters may be introduced through the guidingcatheter to verify the success of the procedure.

FIG. 6D shows target vessel and ostial wall after the CAS 10 and guidingcatheter have been removed from the body and the ablated tissue in theostial wall remains.

FIG. 6E is a three dimensional sketch showing a representation of theoverlapping areas of ablation in the ostial wall from each needle 19that form a ring around the ostium of the target vessel after theprocedure using the CAS 10 has been completed. While FIG. 6E showsoverlapping circles to highlight the ablation from each needle 19, inreality because ethanol disperses readily in tissue, the circles wouldactually blend together.

FIG. 7 is a longitudinal cross sectional drawing of the proximal end ofthe present invention CAS 10. The proximal end of the inner tube 18 isattached to a Luer fitting 38 that can be used to inject fluid to flushthe guide wire lumen 13 inside of the inner tube 18. The guide wire 20is inserted through the guide wire lumen 13. The proximal end of themiddle tube 14 is attached to the side tube 34 with lumen 36. Theproximal end of the side tube 34 is attached to the Luer fitting 36which can be attached to a syringe or balloon inflation device toinflate and deflate the balloon 16 of FIGS. 1 and 2. The lumen 36 is influid communication with the balloon inflation lumen 24 that liesbetween the middle tube 14 and the inner tube 18. The proximal end ofthe outer tube 12 is connected to the distal end of the side tube 32with lumen 33. The side tube 32 is connected at its proximal end to theLuer fitting 31 that can be connected to a syringe or fluid injector toinject an ablative substance such as ethanol through the lumen 33 intothe injection lumen 22 through the injector tubes 15 and out the needles19 into the ostial wall of the target vessel. Additional valves andstopcocks may also be attached to the Luer fittings 35 and 31 as needed.

FIG. 8 is a longitudinal cross sectional drawing of an alternativeversion of the injector needle 49 of the CAS 40 with two differencesfrom that shown in FIG. 3. First, here the injector needle 49 is thesharpened distal end of the self-expanding tube 45 with injector tubelumen 41 while in FIG. 3 the self-expanding tube 15 was attached to aseparate injector needle 19 with lumen 21. The penetration limitingmeans of this embodiment is the limiter 50 with tubular section 52 thatis attached to the outside of the tube 45 with self-expanding legs 57Aand 57B that will open up as the CAS 40 is deployed. The limiter 50would typically be made from a single piece of NITINOL preset into theshape shown with at least 2 self-expanding legs. The major advantage ifthis design is that the penetration limiting means takes up very littlespace within the guiding catheter used for device delivery making iteasier to slide the CAS 40 through the guiding catheter. Although twolegs 57 A and 57B are shown it is conceived that 1, 3, 4 or more legscould be attached to the tube 45 to act as a penetration limiting memberor means when the needle 49 is advanced to penetrate the ostial wall ofthe target vessel.

FIG. 9 is a longitudinal cross section of the distal portion of the CAS40 with the injector needle 49 and limiter 50 of FIG. 8 with theinjector tubes 45 shown collapsed inside an insertion tube 60 withhandle 65 used to insert the CAS 40 into the proximal end of a guidingcatheter or sheath. This is how the CAS 40 would be typically packagedalthough the insertion tube 60 might be packaged proximal to theinjector tubes 15 where the insertion tube 60 would be slid in thedistal direction to collapse the injector tubes 15 just before the CAS40 is inserted in the guiding catheter or sheath. Such an insertion tube60 could be used with all of the embodiments of the present inventiondisclosed herein. The steps to prepare it for use would be as follows:

-   -   1. Remove the sterilized CAS 40 from its packaging in a sterile        field.    -   2. Flush the guide wire lumen 13 with saline solution.    -   3. Access to the left atrium via a large peripheral vein, such        as the femoral vein, typically with the insertion of a sheath.    -   4. Use a trans septal approach to get into the left atrium, via        the vein, to the right atrium, to enter the left atrium. This        approach is a well known procedure.    -   5. Advance a guide wire and guiding catheter across the        inter-atrial septum into the left atrium.    -   6. Using a guiding catheter or guiding sheath with a shaped        distal end, engage the first targeted pulmonary vein. This can        be confirmed with contrast injections as needed.    -   7. Advance a guide wire through the guiding catheter into the        pulmonary vein.    -   8. Insert the proximal end of the guide wire into the guide wire        lumen 13 of the CAS 40 and bring the wire through the CAS 40 and        out the proximal end Luer fitting 38 of FIG. 7.    -   9. Place the distal end of an insertion tube 60 which constrains        the distal end of the CAS 40 into the proximal end of the        guiding catheter. There is typically a TuohyBorst fitting        attached to the distal end of a guiding catheter to constrain        blood loss. The insertion tube 60 can be pushed through the        opened Tuohy-Borst fitting and the Tuohy-Borst fitting closed on        its outside to hold it in place.    -   10. Advance the distal end of the CAS 40 out of the insertion        tube 60 and into the guiding catheter.    -   11. Advance the CAS 40 (or 10) through the guiding catheter 30        of FIG. 6A, and tracking over the guide wire 20, until the        unexpanded tubes 45 (or 15) are located just proximal to the        distal end of the guiding catheter 30. This is shown in FIG. 6A.    -   12. Advance the CAS 40 or 10 over the guide wire 20 until the        balloon 16 used for centering is within the target vessel.    -   13. Expand the balloon 16 used for centering until it is just        slightly less (1-4 mm less) than the diameter of the target        vessel. This will ensure that the distal portion of the CAS 40        or 10 will be roughly “centered” within the target vessel to        enable the circumferential deployment of the expandable tubes 45        or 15 centered around the target vessel ostium so that injection        into the ostial wall will be centered around the ostium of the        target vessel.    -   14. Pull back the guiding catheter 30 so that the self-expanding        injector tubes 15 open. The circumference of the tube 15        expansion can be adjusted in vivo by varying the distance of the        pullback of the guiding catheter 30. That is, if one wants a        smaller diameter (circumference) of expansion to fit the ostial        dimension of that specific target vessel, one can partially        constrain the injector tube 15 expansion by not fully retracting        the guiding catheter 30 beyond the proximal end of the injector        tubes 15. However, the preferred method is to have the final        opening distance be preset for the CAS 40 or 10, with the        injector tubes 45 (or 15) fully expanded to their maximum        diameter governed by their memory shape. Typically the CAS 40 or        10 maximum diameter of the injector tubes 15 would be        pre-selected based on the anticipated or measured diameter of        the ablation ring to be created, such that the fully expanded        injector tubes create the correctly sized ablation “ring.” This        step is portrayed in FIG. 6B.    -   15. Advance the CAS 40 or 10 until the injector needles in the        self-expanding injector tubes 45 (or 15) penetrate the ostial        wall, as seen in FIG. 6C with the penetration depth being a        fixed distance limited by the penetration limiting members 17 of        FIG. 6C or 50 of FIGS. 8 and 9.    -   16. Attach a syringe or injection system to the Luer fitting 35        of FIG. 7.    -   17. Prior to injection of the “ablative” fluid such as alcohol        engagement of the ostial wall could be confirmed by injection of        a small volume of iodinated contrast via a syringe through the        Luer fitting 35 and out of the needles 49 or 19 of FI G. 6C. If        there is contrast “staining” of the tissue this will confirm        that the needles 49 or 19 are engaged into the tissue and not        free floating in the left atrium or aorta.    -   18. Inject an appropriate volume of ethanol (ethyl alcohol) or        other appropriate cytotoxic fluid from the syringe or injection        system through the catheter and out of the needles 49 or 19 into        the ostial wall. A typical injection would be 1-10 ml. This        should produce a multiplicity of interlocking circles of        ablation (one for each needle) that will run together and        intersect to form a ring or ablated tissue around the ostium of        the target vessel as is seen in FIG. 6E.    -   19. In some cases, one may rotate the CAS 20-90 degrees and then        repeat the injection to make an even more definitive ring of        ablation.    -   20. Retract the CAS 40 or 10 back into the guiding catheter 30        which will collapse the self-expanding injector tubes 45 or 15.    -   21. The same methods as per steps 6-19 can be repeated to ablate        tissue around the one or more of the other pulmonary veins        during the same procedure, as indicated to ensure AF ablation or        the 2nd Renal artery in the treatment of hypertension.    -   22. Remove the CAS 40 (or 10) from the guiding catheter 30        completely pulling it back into the insertion tube 60. Thus if        the CAS 40 (or 10) needs to be put back into the body it is        collapsed and ready to go.    -   23. When indicated, advance appropriate diagnostic        electrophysiology catheters through the guiding catheter to        confirm that the ablation has been successful.    -   24. Remove all remaining apparatus from the body.

A similar approach can be used with the CAS, via access from aperipheral artery such as the femoral artery, to treat hypertension, viaablation of tissue in the periostial aortic wall tissue surrounding oneor both of the renal arteries, with the goal of ablating afferent and/orefferent sympathetic nerve fibers entering or exiting the kidney.

While the proximal end of the metallic injector tubes 15 and 45 shownhere terminate in the injector manifold 11, it is also envisioned thatthese tubes could connect to wires that run to the proximal end of theCAS to allow the injector needles 19 and 49 to act as electrodes forsensing signals from the ostial wall of the target vessel as well aspotentially delivering electrical stimulation or higher voltages andcurrents to ablate the tissue in the ostial wall by electrical or RFablation.

FIG. 10 is a three dimensional sketch of an other embodiment of the CAS70 that uses a balloon 76 to expand the expandable injector tubes 75used to deliver the ablative substance to the ostial wall of the targetvessel through the injection needles 79. The 8 injector tubes 75 connectto the manifold 71 that is free to slide distally and proximally alongthe catheter outer tube 74 as the balloon 76 is inflated and deflated.The manifold 71 connects the lumens of the injector tubes 75 to the tube72 with fluid injection lumen 81. The tube 72 connects to a fitting atthe proximal end of the CAS 70 such as the Luer fitting 33 of FIG. 7. Asource of ablative fluid would attached to the fitting and be used toinject the ablative fluid through the fluid injection lumen 81 of thetube 72 into the expandable tubes 75 and out the injection needles 79into the ostial wall of the target vessel. The balloon 76 is inflatedand deflated by delivery of a fluid through the lumen formed between theouter tube 74 and the inner tube 78. The proximal shaft 84 of theballoon 76 is attached to the outside of the outer tube 74 and thedistal shaft 82 of the balloon 76 is attached to the outside of theinner tube 78. The inside of the inner tube 78 provides a guide wirelumen 85 for the guide wire 20. The distal end of the inner tube 78includes a radiopaque marker 73 to assist in visualizing the distal endof the CAS 70 as it is inserted into the target vessel. The balloon 76includes a distal shaft 82, a proximal shaft 84, a proximal conicalsection 87, a central cylindrical section 88, and a distal conicalsection 89. The injector tubes 74 are attached to the outside of thecentral cylindrical section 88 of the balloon 76 and are also held bythe expandable band 77 that covers the outside of the injector tubes 75and the central cylindrical section 88 of the balloon 76. While theexpandable band 77 is shown in FIG. 10 as covering only the centralcylindrical portion 88 of the balloon 76, it is envisioned that it mightalso extend in the proximal direction to cover the injector tubes 75over their entire length proximal to the needles 79 which would make asmoother outer surface of the CAS 70 over this portion. The needles 79extend in the distal direction from the distal end of the injector tubes75 and may be made of a standard needle material such as stainless steelor a more radiopaque material such as tantalum or tungsten or platedwith a radiopaque material such as gold or platinum. The expandable band77 also serves the purpose for the CAS 70 of being the penetrationlimiting member located proximal to the distal end of each needle 70that only allows each needle 70 to penetrate a preset distance into theostial wall of the target vessel. In this embodiment the penetrationlimiting member 77 should limit needle penetration to a depth between0.5 mm and 1 em. It is also envisioned that the entire CAS 70 could becovered by a sheath (not shown) that would protect the needles 79 fromcoming into contact with the inside of the guiding catheter used todelivery the CAS 70 to the target vessel. The sheath would be slid backin the proximal direction once the CAS 70 is positioned with the guidewire 20 within the target vessel. The CAS 70 can also be used with aninsertion tube 60 as shown in FIG. 9.

The balloon 76 can be either an elastic balloon or a semi-compliant ornon-compliant balloon such as used in angioplasty catheters. Such aballoon is typically inflated with normal saline solution including acontrast agent.

It is also envisioned that the best way to protect the needles 79 of theCAS 70 would be to have an elastic band (not shown in FIG. 10) attachedto the distal shaft of the balloon 82 or the inner tube 78 (or both)cover the distal ends of the needles 79 in the pre-deployment condition.Inflation of the Balloon 76 would pull the needles 79 in the proximaldirection out from under such an elastic band. Such an elastic bandwould prevent the needles 79 from catching on the inside of the guidingcatheter as the CAS 70 is advanced into the body.

For this embodiment of the CAS 70, the method of use would be thefollowing steps:

-   -   1. Remove the sterilized CAS 70 from its packaging in a sterile        field.    -   2. Flush the guide wire lumen 85 with saline solution.

Access to the left atrium via a large peripheral vein, such as thefemoral vein, typically with the insertion of a sheath.

Use a trans septal approach to get into the left atrium, via the vein,to the right atrium, to enter the left atrium. This approach is a wellknown procedure.

Advance a guide wire and guiding catheter across the inter-atrial septuminto the left atrium.

Using a guiding catheter or guiding sheath with a shaped distal end,engage the first targeted pulmonary vein. This can be confirmed withcontrast injections as needed.

Advance a guide wire through the guiding catheter into the pulmonaryvein.

Insert the proximal end of the guide wire 20 into the guide wire lumen85 of the CAS and bring the wire 20 through the CAS 70 and out theproximal end Luer fitting 38 of FIG. 7.

Place the distal end of an insertion tube 60 of FIG. 9 which constrainsthe distal end of the CAS 70 into the proximal end of the guidingcatheter. There is typically a Tuohy-Borst fitting attached to thedistal end of a guiding catheter to constrain blood loss. The insertiontube 60 can be pushed through the opened Tuohy-Borst fitting and theTuohy-Borst fitting closed on its outside to hole it in place.

Advance the distal end of the CAS 70 out of the insertion tube 60 andinto the guiding catheter.

Advance the CAS 70 through the guiding catheter, and tracking over theguide wire 20, until the distal marker band 73 is located just proximalto the distal end of the guiding catheter.

Advance the CAS 70 over the guide wire 20 until the marker band 73 iswithin the target vessel and the distal shaft 82 of the balloon 76 isjust proximal to the target vessel.

Pull the guiding catheter back so that the balloon 76 is now distal tothe distal end of the guiding catheter.

Inflate the balloon 76 until it is the appropriate diameter which isbetween 1 and 10 mm larger in diameter than the target vessel.

Advance the CAS until the injector needles in the injector tubes 75penetrate the ostial wall, with the penetration depth being a fixeddistance limited by the expandable band 77. The distal conical sectionof the balloon 76 will act to center the CAS 70 as it is advanced intothe target vessel.

Attach a syringe or injection system to the Luer fitting 35 of FIG. 7that provides ablative fluid that will be injected into the ostial wall.

Engagement of the ostial wall could be confirmed by injection of a smallvolume of iodinated contrast via a syringe through the Luer fitting 35and out of the needles 79 prior to injection of an “ablative” fluid suchas alcohol. If there is contrast “staining” of the tissue this willconfirm that the needles 79 are engaged into the tissue and not freefloating in the left atrium or aorta.

Inject an appropriate volume of ethanol (ethyl alcohol) or otherappropriate cytotoxic fluid from the syringe or injection system throughthe lumen 81 of the tube 82 and out of the needles 79 into the ostialwall. A typical injection would be 1-10 ml. This should produce amultiplicity of interlocking circles of ablation (one for each needle)that should intersect to form a ring around the ostium of the targetvessel as is seen in FIG. 6E.

Deflate the balloon 76 and retract the CAS 70 back into the guidingcatheter.

In some cases, one may rotate the CAS 70 between 20-90 degrees and thenrepeat the injection to make an even more definitive ring of ablation.

The same methods as per steps 6-20 can be repeated to ablate tissuearound the one or more of the other pulmonary veins during the sameprocedure, as indicated to ensure AF ablation or the 2nd Renal artery inthe treatment of hypertension.

Remove the CAS 70 from the guiding catheter completely pulling it backinto the insertion tube 60. Thus if the CAS 70 needs to be put back intothe body it is collapsed and ready to go.

When indicated, advance appropriate diagnostic electrophysiologycatheters through the guiding catheter to confirm that the ablation hasbeen successful.

Remove all remaining apparatus from the body.

A similar approach can be used with the CAS 70, via access from aperipheral artery such as the femoral artery, to treat hypertension, viaablation of tissue in the periostial aortic wall tissue surrounding oneor both of the renal arteries, with the goal of ablating afferent and/orefferent sympathetic nerve fibers entering or exiting the kidney.

While the CAS 70 shows a separate tube 72 it is envisioned the fluidinjection lumen of the CAS 70 catheter body could be constructed similarto that of the CAS 10 of FIGS. 1-5 where an additional outer tube wouldbe placed with the fluid injection lumen being between the outer andmiddle tubes. It is also envisioned that instead of concentric tubeswith lumens between the tubes, a multi-lumen catheter could be used withseparate lumens formed during extrusion of the catheter body. Similarly,while the shape of the tubes and lumens shown here are cylindrical,other shapes are also envisioned.

While the present invention described here has an expandable balloon asa centering means, it is envisioned that a fixed diameter centeringsection could be used or a mechanical expandable structure could alsofacilitate centering of the CAS. While the version of the CAS shown hereis an over the wire design, it is also envisioned that a rapid exchangeguide wire system where the wire exits the catheter body at a locationbetween the proximal end and the fluid injection ring would be feasiblehere. In addition, a fixed wire design such as that shown by Fischell etal in U.S. Pat. No. 6,375,660 for a stent delivery catheter would alsowork here.

Various other modifications, adaptations, and alternative designs are ofcourse possible in light of the above teachings. Therefore, it should beunderstood at this time that within the scope of the appended claims theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A method of treating a target tissue, the methodincluding: advancing an ablation system through a target vessel until adistal end of the ablation system lies near the target tissue, theablation system including at least a guiding catheter, adiameter-increasing structure, an inner tube, and two needles; advancingthe diameter-increasing structure of the ablation system from a firstposition within the guiding catheter to a second position outward fromthe guiding catheter toward and against a lumenal wall of the targetvessel to position the distal end generally equidistant from two pointsof the lumenal wall, wherein the diameter-increasing structure does notpenetrate the luminal wall and wherein the inner tube is located distalto the diameter-increasing structure; after advancing thediameter-increasing structure toward the lumen wall, advancing the twoneedles outward around a circumference and at least partially throughthe lumenal wall of the target vessel at the two points and into thetarget tissue and wherein the inner tube is located distal to the twoneedles; and evaluating electrical activity with at least one needle ofthe at least two needles, wherein the at least one needle acts as adiagnostic electrode; and simultaneously injecting ablative fluidthrough the two needles into the target tissue.
 2. The method of claim 1where the at least one needle is electrically connected to a proximalend of the ablation system.
 3. The method of claim 1 further includingdelivering electric current or RF energy to the target tissue.
 4. Themethod of claim 1 where the at least one needle senses signals from thetarget tissue.
 5. The method of claim 1 where the ablative fluidcomprises ethyl alcohol.
 6. The method of claim 1 where thediameter-increasing structure is a mechanical structure.
 7. The methodof claim 1 further including limiting the penetration of the at leasttwo needles into the target tissue.
 8. The method of claim 1 where thetwo needles are coupled to a manifold.
 9. The method of claim 1 whereone or more of the needles is electrically connected to a proximal endof the ablation system.
 10. The method of claim 1 where one or more ofthe needles acts as a diagnostic electrode for evaluation of theelectrical activity in the area of an ostial wall.
 11. The method ofclaim 1 where one or more of the needles act as diagnostic electrodesfor measurement of electrical activity within an ostial wall of thetarget vessel.
 12. The method of claim 1 where one or more of theneedles act as electrodes for sensing signals from an ostial wall of thetarget vessel.
 13. The method of claim 1 where the depth of penetrationof the one or more needles is limited.
 14. The method of claim 1 wherethe diameter-increasing structure is manually expandable.
 15. The methodof claim 1 further including producing a multiplicity of interlockingcircles of ablation.
 16. The method of claim 1 further includingproducing a ring of ablated tissue.
 17. The method of claim 1 furtherincluding advancing one or more diagnostic electrophysiology catheters.18. The method of claim 1 wherein at least one needle has a stop whichlimits further penetration into the tissue.
 19. The method of claim 1wherein the two needles penetrate a preset distance into the targettissue until further advancement is simultaneously limited.
 20. Themethod of claim 1 wherein the two needles penetrate a preset fixeddistance of between 0.5 mm and 1 cm into tissue based on a position of astop.